Cooking oils and cooking fats are food grade products typically obtained from plant or animal origin. Cooking oils include sunflower oil, peanut oil, canola oil, safflower oil and olive oil. Vegetable oils may also be treated to obtain margarine. Cooking fats, such as tallow and lard, typically come from animal origins.
The raw oils and fats normally contain a number of compounds that render those products unpleasant or unpalatable. These compounds include compounds that result in undesirable taste, colour and odour. In order to improve the commercial acceptability of such products, the cooking oils and cooking fats are normally treated to remove those undesirable compounds.
The normal method of treatment involves contacting the cooking oils and cooking fats with a clay-based adsorbent material. The adsorbent material is often an acid-activated clay that adsorbs the undesirable compounds from the cooking oil or cooking fats. The fats may be thus-treated at elevated temperature to place the fats into the liquid state.
Once the adsorbent material has adsorbed its capacity of undesirable compounds, it is loaded with such compounds and cannot adsorb any more. At this stage, the loaded adsorbent is removed from the adsorbing apparatus and replaced with fresh adsorbent.
The waste adsorbent recovered from the treatment of cooking oils and cooking fats is loaded with adsorbed compounds. Consequently, it has effectively no remaining capacity for adsorption. Furthermore, the waste adsorbent contains residual amounts of oils or fats therein, despite the waste adsorbent being treated to remove as much oil or fat as possible therefrom. As a result, further use or disposal of the waste adsorbent is problematical.